After
Debra catches Dexter in the act of killing Travis at the church, Dexter
persuades her that they need to destroy the evidence, and suggests
starting a fire to make it look like Travis committed suicide in a
final tableau.

So in this brief scene, Debra goes out to get gasoline, to burn down the church.

We see her at the station, filling a large red gas can, and nervously looking around, afraid that someone will see her.

Q.
What is it actually in real life?

A. A gas station.

Q.
Where can I find it in real life?

A. This was shot at the Mobil station at 5857 W. Sunset Blvd, at the northeast corner of Sunset & Bronson Ave,in Hollywood.

That is just two blocks east of the Sunset-Gower studio, where they film Dexter.

(It's about two miles north of the other gas station, seen earlier in this episode, where Dexter had his credit card declined.)

She is using the tank on the station's west side, and the camera is looking north.

A. In the early seasons, I usually had to hunt down the locations after viewing the episodes,
using clues from the various scenes. By the now, though,
I've developed a small group of fans, spies & tipsters who kept an
eye out for Dexter filming in their neighborhoods, and would let me know
in advance when something was about to film there.

Between those reports, my own personal reconnaissance around town, and a
few new resources I discovered, by the time the first episode airs, I
already know most (but not all) of the filming locations, and only
need to watch the episodes and match up the scenes with the correct
locations.

This group of helpful fans includes Rick, Joel, Ellen, Susan, Jeff, Kerry, and others. My thanks to all of
them.

This tip came from Rick, and was easily confirmed via StreetView. (Thanks, Rick!)